The clerical committee that vets election candidates in Iran barred two important contenders from the ballot for next month's presidential election, virtually guaranteeing that the next head of government will be loyal to the regime of Supreme Leader Ayatollah Ali Khamenei.

Iran's Guardian Council disqualified former President Ali Akbar Hashemi Rafsanjani and Esfandiar Rahim Mashaei, an aide to President Mahmoud Ahmadinejad, from...